The transducer of this invention is intended to have particular application for detecting differences in fluid pressure in two separate fluid lines which are connected in a fluid system. For instance, the system may be a hydraulic system utilized in vehicles, including tractors, trucks, and the line, and the system would commonly include a hydraulic filter element which is receiving hydraulic fluid for the usual purpose of filtering and cleaning the fluid. However, the hydraulic system mentioned commonly becomes contaminated to a degree where the hydraulic flow is no longer tolerable or satisfactory, and that might occur when the equipment is used under conditions which are conducive to such contamination, even though the recommended schedule for changing the filter is abided by. That is, the change recommendation is commonly based on a length of time or a number of operation hours or other length of time, but that criteria is not always satisfactory and the filter can become clogged even though the recommended change interval is followed. Many factors make the recommended change interval inadequate in actual practice, and those factors include varying environmental operating conditions, cleanliness of the fluid added to the system, failure of components within the system, servicing procedures, and the like. Consequently, the user does not know when the filter actually needs to be changed, and even following the recommended change interval is not always the answer.
The problem with the filter element in the hydraulic system mentioned is that the user does not know when the filter needs to be changed, and that change should occur when the differential fluid pressure across the filter element exceeds a minimum amount. The present invention provides a transducer which is connected to the fluid-pressure lines across the filter element, and the transducer is arranged for detecting the pressure differential and to thereby indicate when the filter element needs to be changed. Of course the transducer of this invention is not limited in its application to monitoring the filter element in a hydraulic system, but it is useful wherever it is desirable to detect a fluid-pressure difference in two fluid lines.
Accordingly, it is the objective of this invention to provide a differential fluid-pressure transducer which will accurately and readily indicate the pressure difference in two fluid-pressure lines. Further, in accomplishing the aforementioned objective, the present invention provides the transducer at a relatively low cost and permits the use of common instruments to be actuated by the transducer and thereby govern monitor items such as relief valve settings, fluid line pressure drops, pressure drops through control valves, and simply having a guage or the like for visual indication of pressure differences in two fluid lines, and the transducer can also be used to actuate conventional switches or the like.
Other objects and advantages will become apparent upon reading the following description in light of the accompanying drawings.